Currently, a network transmission mode used in a communications device is generally configured such that a device at a transmitting end and a device at a receiving end communicate data by using a same transmission protocol. Common transmission protocols include the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), the Bluetooth Serial Port Profile (SPP), and the like. In a transmission process, if data is excessively large, a transmitting device may first segment the data into several data packets according to the transmission protocol, where a sequence number is assigned to each data packet and the device at the transmitting end transmits the data packets to the device at the receiving end sequentially.
A reliable transmission protocol such as the TCP has a retransmission mechanism for lost packets. If a data packet currently received by the device at the receiving end is not a correct data packet, the device at the receiving end instructs the device at the transmitting end to retransmit a correct data packet, and simultaneously continue to receive a next new data packet. For an unreliable transmission protocol such as the UDP, if a data packet currently received by the device at the receiving end is not a correct data packet, the device at the receiving end discards the data packet by default, and continues to receive a next new data packet. Therefore, the reliable transmission protocol is suitable for a service that has an integrity requirement on data, such as file transmission. The unreliable transmission protocol has a fast speed and high efficiency, and is suitable for a service that has a real-time requirement on data, such as streaming media.
However, both the reliable transmission protocol and the unreliable transmission protocol can only meet a part of the service requirements. As such, the existing data transmission modes cannot meet both integrity and real-time service requirements.